It's hard to count the number of cross-border marriages, as they are not registered by civil affairs authorities due to their complexity.
In this March, CDC did the first test on Vietnamese women who married Chinese husbands. Among the 406 tested wives, one was found HIV positive.
"She married her husband four years ago," Zhong said. "He is not infected yet, so we told him to take preventive measures."
CLEANING UP THE SEX TRADE
Prostitution is illegal in China and police have cracked down on the trade in recent years.
To curb the cross-border spread of HIV through sex channel, in addition to the police crackdown, the Pingxiang CDC launched a campaign to ensure the health of Vietnamese sex workers.
He Bo, the director, said that Pingxiang has cooperated with Lang Son of northern Vietnam in the effort. Health officials from China and Vietnam exchange information and technology frequently.
Sex workers receive regular health checks. At the same time, two staff members from the CDC teach sex workers how to protect themselves against HIV.
One of the staff members is Hoang Thu Mai, a Vietnamese woman. The other is Li Bing, a 27-year-old Vietnamese language major.
"Each week I spend two days visiting the Vietnamese sex workers,teaching them basic HIV/AIDS knowledge," she said.
However, she wants to communicate with the Vietnamese sex workers in a more tactical and effective way.
"It is hard to gain their trust," she said. "If I preach all the time, asking them to use condoms, they get bored."
Xu Wenqing, a project officer with the United Nations Children's Fund (UNICEF) who has been working for AIDS programs for years, says the CDC's work is important and necessary.
"Sex is becoming the main channel for transmission of AIDS in China, through which the epidemic spreads from high-risk groups, like drug abusers and prostitutes, to the ordinary people," she said.
According to statistics released by China's Health Ministry, 370,000 people had HIV by the end of last year. The rate of heterosexual transmissions has grown from 40.3 percent in 2008 to 47.1 percent in 2009.
Xu Wenqing suggested that health authorities of China's border areas, like Pingxiang, cooperate more with neighboring countries in sharing information and providing health checks and medical treatment.
At Youyiguan, or Friendship Pass, many young Chinese and Vietnamese, can be seen dragging their suitcases as they walk across the border in twos and threes. Each day about 600 people cross the Pingxiang border.
Overlooking the customs gate is a huge advertising board. On it is a picture of the famous singer Peng Liyuan, China's anti-AIDS ambassador, and wife of vice president Xi Jinping. "AIDS is not curable but could be controlled and prevented," it said.
"To check the spread of AIDS across border through sex channels is difficult, but significant," Xu Wenqing said.
